Most professional woodworkers, metal workers and multiple-run production shops have tools including jigs and fixtures to guarantee that their products are square. Assuring squareness of frame type structures, such as for example drawers, carcasses and frames in varying sizes, without such tools can be problematic. Instruments such as try squares, framing squares and sliding sticks, can be used to check squareness but squaring a frame using these instruments is time consuming and awkward.
An improved apparatus for checking the squareness of frame type structures is needed. It is believed that the squareness testing instrument and method of operation thereof according to the illustrative embodiments described hereinafter provides an effective way of testing the squareness of such frame type structures.